This invention is directed generally to an inspection device, and more particularly to a visual inspection device for visually ascertaining or verifying the correct placement and orientation of a contact lens in a tinting fixture, prior to the commencement of a tinting operation.
So-called "soft" contact lenses have gained considerable popularity. Such soft contact lenses are manufactured from a hydrophilic plastics material, such that they can absorb and retain water and hence become soft and pliable upon such absorption. As a result, the lenses are relatively comfortable for the user to wear and in certain instances can be worn for relatively long periods of time.
It has additionally become increasingly desirable to tint or color these soft contact lenses for reasons, for corrective reasons, or for both. For example, tinted lenses can provide cosmetic improvement for persons having one or both eyes which have been disfigured by illness or accident. Such tinted lenses can also be used by patients suffering from one or more disorders such as diplopia, albinism, or aniridism to improve the appearance of the eyes, and hence improve overall general facial appearance. Such tinted lenses can also aid in reducing light transmission so as to give the patient increased visual comfort.
While a number of methods of coloring contact lenses are known, one particularly advantageous method and related apparatus is disclosed in the co-pending U.S. patent application of Richard Rabenau, et al., Ser. No. 592,694, filed Mar. 23, 1984 now U.S. Pat. No. 4,518,390. This co-pending application discloses a method and a tinting fixture apparatus for producing a tinted or colored lens which provides a natural appearance. This type of tinting fixture may further be specially adapted for use in a novel automated contact lens tinting apparatus of the type disclosed in the co-pending application of Francis E. Ryder, et al., Ser. No. 715,095 filed Mar. 22, 1985, now U.S. Pat. No. 4,632,055, which also discloses such a specially adapted tinting fixture.
The tinted lenses produced by the foregoing method and apparatus have a clear central area, a colored intermediate area of generally annular form and a clear outer area. This pattern generally corresponds to the normally colored appearing iris portion of the eye, without producing color over the normally clear or white-appearing sclera of the eye. Generally speaking it is usually desired that the central portion of the lens be untinted or uncolored so as to permit maximum light passage into the eye. Accordingly, the method and apparatus disclosed in the above-mentioned co-pending application provides the lens with such a ring-like or annular tinted area.
As also discussed in the above-mentioned co-pending application, a number of problems can arise in properly mounting a lens on a tinting fixture so as to in effect mask the areas thereof which are to remain untinted or uncolored and permit the tinting solutions or dyes to reach and react with only that ring-like annular area which is to be tinted or colored. However, it is important that the technician not handle the lens directly with the fingers, since minute amounts of oil present on the fingers, if imparted to the lens, may prevent the dye from being accepted or absorbed evenly by the lens. On the other hand, if the technician uses gloves, dexterity may be reduced; however, dexterity is important in manipulating the small lens and centering the lens on the tinting fixture. If the technician uses tweezers or some similar tool to manually mount the lens on a fixture, the procedure can be slow, and accuracy in mounting may be compromised. In this regard, it will be recognized that if the lens is not properly oriented or centered relative to the fixture, the desired annular tinted or colored area will also fail to be centered as desired on the finished, tinted lens.
As suggested above, it is important that the tinted annular or ring-like area of the lens, as well as the clear central portion be relatively precisely defined and accurately located. That is, slight fuzziness or running of the dye colors into the otherwise uncolored areas of the lens will be immediately apparent. Such fuzziness or tint runs, or such off-center location of the tinted area will of course result in the rejection of the finished lens. As in any manufacturing process, a high rate of rejected products is of course to be avoided, consistent with maintaining an optimum rate of production of finished products.
This application additionally discloses a novel inspection or viewing device and related method for use in the foregoing lens tinting process, for ascertaining or verifying the proper placement and orientation of the lens relative to the tinting fixture. That is, the present invention is directed to an inspection device and method for visually observing the lens, following placement in the tinting fixture, to assure that the lens is properly centered with respect to the fixture and that air bubbles in the surrounding fluid are avoided. These considerations help to assure the proper precise definition and location of the tinted areas of the finished lens product.